Days Retention Time Area Day-1* 2.734 563116 Day -2* 2.736 563076 Day -3* 2.735 561049 Average 2.735 562414 Standard Deviation 0.001 1182 %RSD 0.04 0.21

Table 3: Inter-day precision of the proposed method for Metformin (on three consecutive days n=6) in plasma.